Piston and packing therefor



APl'l 13, 1937. s. T. NELSON 2,077,182

PISTON AND PACKING THEREFOR Filed OC'E. 28; 1933 Patented Apr. 13, 1937 was.; I

U'Nirso This invention relatesy tov packings ofthe type employed in motors and'pumpsofftharecipro; eating piston typeY toeiect ti'ghtjoints "between the contacting walls off the :cylinders and pistons? The present invention`VV has been designed-fonv 'a type of moteror pump disclosed inm-ycoepend# ing application vfor Pump "and rrrotofstructures, ScrialNocMfSvZ, -fl-ledeMay 28:, 19321, wherein. the pistonsvand cyli`nders.-or;A moreelpropcrly speaking, the pistonf-chanrbers, are ofl rectangular cross section, and the ends *of the piston chamd bers areclo'sed` by-removable walls. In the structure of the aforesaid application the side and end walls of the piston, and also the side and end walls of the cylinder or piston chamber are formed with grooves, and these grooves are filled with packing comprising straight packing strips for the side and end walls cooperating with L- shaped corner packing strips, and independent bow springs underlying the packing strips to force the same outwardly into snug sliding contact with the opposing walls.

The primary object of the present invention is to provide an improved packing, which will affor a better seal at the corners.

A further object `is to provide an improved spring backing which may also be removed and replaced as a unit.

Still other objects and attendant advantages of the invention will be apparent to persons familiar with the art from the following detailed description, taken in connection with the accompanying drawing, wherein I have illustrated one simple and practical embodiment of the invention,

and in whichl Fig. 1 is a side elevation of the upper portion of a rectangular piston or plunger, showing my improved packing therein, with the end walls of the piston chamber fragmentarily shown.

Fig. 2 is a similar view to Fig 1, but with the packing strip removed to disclose the underlying spring backing.

Fig. 3 is an end elevation of the upper portion of the piston or plunger, with the side walls of the piston chamber fragmentarily shown, and also showing packing strips in such side Walls engaged with the sides of the piston or plunger.

Fig. 4 is an enlarged sectional plan view on the line 4-4 of Fig. 1.

Fig. 5 is an enlarged sectional plan view on line 5-5 of Fig. 1.

Fig. 6 is a view similar to Fig. 5, showing the main side and end packing strips and their spring 55 backing members meeting in a miter joint.

3; claims. (ci, sta-,gai

-R'eferringto'fthe drawing..` Ill desigriates as an errtiretya rectangular lpiston'body', lier-'ein shown as' of greater'length than-"widthgbut, soI far as the-present irwnltiorik is concerned', the same may beisquar f'Thei side andend.- walls of the body t 'are'ffformedfwith:grooves or channels I-I.` that registerwith' each? other at'their ends; Ori-the bcttomf wallotfeach' groovcfisa: spring `backing for the packing strips, the same preferably consisting of-f comparatively "thin-@flat metal'. strips otherwise/fattsic'l'ied`A at meV end"-a'.` series of bow springs I3. Bearing against the springs I3 are the packing strips, each preferably of sectional structure, as shown, comprising, in the preferred form, upper and lower sections I4 and I5 formed,

at their ends with inter-engaging hooks I4 and I5', respectively, whereby the several sections are connected endwise throughout the full length of the strip. To prevent the sections from falling apart when the strip is removed, I also preferably permanently connect them as by means of a rod or wire I6 extending through the hook portions of all the sections and riveted at its ends against the outer end walls of the end sections. To facilitate the removal and replacement of the packing strips, the end sections of the strips are formed with tapped holes I1, so that, upon the removal of an end wall of the piston chamber, a suitable tool with a threaded end can be screwed into one of the holes I'I, and the strip thus withdrawn. Similarly, by gripping an end of the backing strip I2 by a pair of pinchers, this may also be withdrawn.

Since the side and end grooves II are in the same transverse plane of the piston body, and register with each other at their ends, one opposed pair of packings (the side packings as herein shown) are made of full length, while the other opposed pair are shortened by the depth of the. two grooves, so that the end portions of one opposed pair overlap the ends of the other opposed pair, as clearly shown in Fig. 4. While I have shown the side packings as overlapping the ends of the end packings, this might, of course, be reversed.

Instead of arranging the packings with the end portions of one pair overlapping the ends of the other pair, as above described, I may extend all the packing and backing strips the full length of their respective grooves, and bevel their ends, as shown at Idal and I2a in Fig. 6, so as to form miter corner joints.

In order to aiord a suitable packing of the corner portions of the piston body, I form in such corners, preferably just below registering corners of the grooves IIoblique corner grooves I8, most clearly shown in Fig. 5, and in these grooves are disposed corner blocks I9, preferably of the triangular form illustrated, and` formed with rectangular wear surfaces I9'. To provide a, suitable spring backing for these corner blocks, I preferably attach to the oblique edge of each block a bow spring 20, the free ends of the spring bearing on the bottom wall of the groove I8. The blocks I9 are of a size such that their vend portions lap the end portions of the main side and end packing strips, as clearly shown in Fig.

4, whereby the corner portions as well as the sidesY and ends of the piston body are fully sealed against the side and end walls of the .n piston chamber.

As indicated in Fig. 3, the walls of both the' piston body and the piston chamber are preferably equipped with packing of the type above described located in spaced relation, so as to form a double seal, but this, of course, is optional. I have herein shown and described a form of the invention which in practice has been found to satisfactorily effectuate the stated purposes and objects thereof; but obviously changes may be made in the details without vdeparture from the scope of the invention as dened in the claims;

I claim: y Y 1. The combination with a rectangular piston body formed with side andcorner grooves, of packing therefor, comprising straight packing strips occupying said side grooves, spring backings in said side grooves behind said strips, corner blocks occupying said corner grooves and formed with rectangular Wear surfaces, and individual spring backings in said corner grooves behind said corner blocks.

2. The combination with a rectangular piston body formed with side grooves registering with each other at the corners of the piston body and With Vcorner grooves laterally offset from said side grooves,-of straight packing strips occupying said side grooves with the end portions of one pair of opposed strips overlapping the ends of the other pair of opposed strips, spring backings in'saidside grooves behind said strips, corner packing blocks occupying said corner grooves and formed with rectangular Wear surfaces, and individual spring backings in said corner grooves behind said corner blocks.

3. The combination with a rectangular piston body formed.l with side grooves registering with each other at the corners of the piston body and with corner grooves laterally offset from said side grooves, of straight packing strips occupying said side grooves and formed with oblique ends meeting in miter joints, spring backings in saidrside grooves behind Said strips, corner packingblocks occupying said corner grooves'and formed withrectangular wear surfaces, and individuakspring` backings in said corner grooves` behind said corner blocks. y

, SVEN T. NELSON. 

